This invention relates to dead bolt locks and more particularly to a device preventing pass key retraction of a dead bolt.
1. Field of the Invention
Motels, apartments and the like are customarily provided with dead bolts for security of the occupants against unauthorized entry of the premises.
However, the owner and maintenance personnel are also customarily provided with a pass key permitting them to enter the respective room or suite.
Occasionally the pass key or a duplicate thereof is obtained by unauthorized persons who may then gain entry to the premises while occupied by a customer or a renter.
This invention provides a manually manipulated locking arm member which substantially envelops the dead bolt operating knob on the inside of an entry door to prevent angular rotation of the knob and withdrawing the dead bolt by the use of a pass key.
2. Description of the Prior Art
I am not aware of any patent which discloses immobilizing the knob of a dead bolt lock to prevent unlocking a dead bolt lock by a key.